This invention relates to apparatus and a corresponding method of forming stiffening panels for use with palletainers and other types of storage containers.
"Palletainers" is a term used in the art to designate containers intended for use in association with pallets to hold materials, such as vegetables, in cold store. A palletainer comprises a cardboard structure known as a "sleeve". The container sleeve defines the side walls of a container for materials.
In order to maintain the requisite rectangular shape of the cardboard sleeve of the palletainer, an internal stiffening structure or skeleton is provided. Such a skeleton is in the form of stiffening panels for the side walls of the sleeve and the panels are inserted into the sleeve of the palletainer so as to lie substantially face-to-face therewith.
A stiffening panel for a palletainer comprises a planer panel or flat cardboard sheet carrying a plurality of transverse stiffening elements or ribs of a V section, these being bonded to the planer panel. Four such panels are inserted into the palletainer sleeve, one for each face, with the ribs on the inboard face of each panel. Palletainers and stiffening means therefore are described in my Patent number GB 2269580.
It has been found that the construction of stiffening panels formed with bonded ribs is difficult and time consuming, particularly with respect to the correct formation of the stiffening ribs and secure bonding of same to the planer panels.
An object of the invention is to provide apparatus and a method offering improvements in relation to matters discussed above and elsewhere herein or improvements generally.
According to the invention there is provided apparatus and methods as defined in the accompanying claims.
In an embodiment of the invention there is provided apparatus for forming reinforced stiffening panels for use with palletainers or like product containers wherein reinforcement of panels is provided by stiffening elements in the form of ribs wherein means are provided to form said ribs by the shaping and folding of a rib blank and securing same to said panel.
The apparatus for forming stiffening panels having stiffening elements in the form of ribs comprises a substantially horizontal support means or bed onto which a planer panel may be received. Located above the bed are a plurality of forming assemblies which act to shape and fold the stiffening ribs. Each station is adapted to receive a rib blank, fold and shape the blank into the required configuration, generally being of a V-shaped section and secure it to the planer panel.
The rib blank generally consists of a pre-creased strip of corrugated card or the like. Pre-creased blanks are made by a stamping/creasing process and machine (not shown). The creases formed therein generally comprise a central primary crease and two secondary creases placed one on either side of the primary crease. The advantage of using a pre-creased rib blank is that when the blank is shaped and folded, such folding is predictable occurring along the lines of the creases. It also facilitates "clean" folding and is energy efficient as less energy is required to produce a fold along a crease as would be required to produce a fold in a non-creased blank.
The forming assemblies comprise a support means for a rib blank, a first forming element or forming bar, roller means, an adhesive reservoir and a second forming element or former, together with means for actuating the abovementioned elements. The forming assemblies are supported on a framework, located above the bed, and are moveable in respect to one another on the framework. This enables the stations to be moved closer together or further apart depending on the specification of the panels required, namely the number and relative spacings of the ribs on any particular panel.
Support means such as locating brackets, guide rails, runners or frame are provided to give initial support to a rib blank during the shaping and folding operation/process. The support means extend along the length of the bed and outwardly past and to one side of the apparatus. In addition to providing initial support to the rib blank, the guide acts as a feeder means by which the rib blank is presented in the required position for shaping and folding.
When the rib blank is placed on the supporting frame, one end of the blank abuts spaced rollers. When activated, the rollers exert a gripping action on the edge of the roller and cause it to be moved along the guide into a second position located above the bed.
As the rollers begin to act on the rib blank, a measured amount of a hot melt adhesive is dispensed to the rollers from an adhesive reservoir, each forming assembly has a dedicated adhesive reservoir. As the rollers advance the rib blank, they act to distribute the adhesive along the edges of the rib blank.
As the rib blank moves along the guide so as to be located above the bed, a forming bar is also caused to advance, with the rib blank, towards the bed. The forming bar is located beneath the support for the rib blank. Each forming station is provided with a forming bar. The forming bar is generally an elongate metal fabrication. The particular shape and configuration of the forming bar is dependent on the shape required for the stiffening element. When a stiffening element of substantially V-shaped cross section is required, the cross sectional shape of the forming bar is of an inverted T.
Located above the bed onto which the planer panel is received is a former, each forming assembly has a dedicated former. Each former comprises a substantially inverted V shaped elongate metal fabrication, the sides or arms of the inverted V have a hinged or spring loaded edge portion. The edges of the sides or arms of the fabrication are finished with a rounded or rolled edge which prevents the edge catching on and possibly tearing the material of the rib blank. Actuating means, such as hydraulic or pneumatic rams are provided which act to move each former in a generally downwardly direction towards the rib blank.
In use, a planer panel to receive reinforcing ribs is fed into the apparatus and located on the bed. Pre-creased rib blanks are placed on the guide frame with the non creased side uppermost and are moved along the guide frame by the rollers so as to be located above the planer panel. As the rib blank moves along the guide frame, a measured amount of adhesive is delivered to the edges of the blank. As the blank advances towards the bed, the forming bar also advances towards the bed, being located below the rib blank. Both are moved sufficiently over the bed so as to be located beneath the former.
Once the rib blank and the forming bar are in the required position, beneath the former, actuation means cause the former to move in a downwardly direction towards the rib blank. Continued movement of the former causes it to come into direct contact with the rib blank. This continued downward pressure causes the blank to be dislodged from the guide rail and brought into contact with the forming bar located beneath it. The area of contact between the rib blank and the upstanding portion of the forming bar is the region of the primary crease. The pressure applied by the former acting on the blank which is now in contact with the forming bar, said forming bar resisting this downward pressure. This causes the blank to fold along the central pre-formed crease, around the forming bar. Due to the substantially triangular shape of the former, one arm of the former passes either side of the forming bar. The hinged or spring loaded edges or arms of the former act to exert a gripping action on the blank as it is bent around the former. This gripping action is exerted in the region of the remaining pre-formed creases and serves to prevent the blank from flattening out as it is bent around the forming bar but rather to push or "pinch" together the regions of the blank which have been bent around the forming bar. The action of the spring loaded arms in preventing the blank from flattening out as it is folded along the crease serves to form the sides of the rib which is upstanding from the planer sheet and substantially triangular. The rolled or rounded edges of the spring loaded or hinged portions of the former assist the pinching action by moving cleanly over the surface of the rib blank and presenting no sharp edges which may "catch" on the rib blank and cause damage.
The gripping or pinching action of the former also acts to assist the bonding of the formed rib to the planer panel. By exerting pressure in the region of secondary preformed creases in the rib blank to "pinch" the sides of the forming rib together, this results in the region of the rib blank between the secondary pre-formed creases and the longitudinal edge of the blank retaining a substantially horizontal attitude. The continuing downward pressure of the former pushes the rib blank from the guide rails and towards the planer panel. This causes the substantially horizontal regions of the rib blank to contact the upper face of the planer panel. The adhesive which is carried on the edges of the rib blank cures and bonds the now shaped and formed rib to the planer panel.
Once the rib has been shaped, formed and bonded to the planer panel, the former is moved away from the bed in an upwardly direction and the forming bar is retracted away from the bed. The planer panel, now bearing reinforcing ribs, is removed from the bed and the process repeated.
In a further embodiment of the invention there is provided a method of forming re-enforced stiffening panels for use with palletainers or like product containers wherein reinforcement of panels is provided by stiffening elements in the form of ribs comprising the steps of causing folding and shaping of a rib blank to form a rib and the step of securing same to a panel.